until.ts

try-catch.ts

/** 
  Value first, might be nicer

  @example
  const [value] = tryCatch(doSomething())
  if (!value) {
    // something went wrong
  }
*/
const tryCatch = async <TSuccess, TError extends Error>(
  promise: Promise<TSuccess>
): Promise<[result: TSuccess | null, error: TError | null]> => {
  try {
    return [await promise, null];
  } catch (err) {
    return [null, err as TError];
  }
};

until.ts

export async function until<TPromise extends PromiseLike<unknown>>(
  promise: TPromise
): Promise<
  [error: unknown | undefined, result: Awaited<TPromise> | undefined]
> {
  try {
    return [undefined, await promise];
  } catch (err) {
    return [err, undefined];
  }
}